The present invention relates to a method and apparatus of using a relay station to assist processing of requests from user ends (UEs).
In a cellular mobile radio communication system, when a base station has a very high covering capability and very large coverage, there may be the following problem: when a user end is at the edge of the coverage of the base station, the signal received by the base station from the user end will have a poor quality due to relatively low transmitting power of the user end and even worse the signal sent from the user end cannot be received properly.
A solution to this problem is to add a relay station (RS) in the area covered by the system. By adding a relay station in the radio cellular system to develop a multi-hopping capability, it will not only extend the covering area of the system and cell capability but also will have such advantages as reduced transmitting power of user ends and prevention of serious shadow areas. The solution of adding a relay station in a cellular mobile radio communication system has been widely adopted in the art and FIG. 1 is a diagram illustrating the architecture of a cellular mobile radio communication system with a relay station.
When the relay station is added to the cellular system, an overall planning of the system can be made as well. A feasible solution is to build a cellular system controlled by a base station. The concept is that the base station sends signaling to all user ends and responds to requests sent from individual user ends. To do this, how the relay station is used to assist end users and to forward the uplink requests of the end users to the base station is a significant challenge. Recently, there is emerging attention to how a relay station can be added to a cellular mobile radio communication system and studies of how the relay station can be used to forward the uplink requests from the user ends have started.
A method for using a relay station to forward uplink requests of end users in a cellular mobile radio communication system is that the relay station will not process the uplink requests received from the user ends but will immediately send the uplink requests received to the base station upon receipt.
The shortcoming of this method is that when the relay station receives a large number of uplink requests from the user ends, the need of immediate forwarding of all uplink requests received to the base station will result in forwarding of large number of messages at the same time, which will greatly increase the load on the relay station. In addition, the direct forwarding of uplink requests by the relay station will greatly increase the frequency at which the radio resources between the relay station and the base station are used, leading to waste of system radio resources, in particular when there are a large number of relay stations in the coverage of the base station, which may even exhaust the radio resources.